In March of 1991, Mark joined A CHORUS LINE, THE BROADWAY TOUR OF AMERICA. Debuting at Boston's Wang Center, he played Mike Costa, the energetic gypsy who tells about watching his sister dance and declaring "I Can Do That".

In addition to playing Mike, Mark understudied the roles of Richie (Give me the Ball) and Paul. In a ten-minute monolouge, Paul tells his touching story about shame and acceptnace. Mark made his debut as Paul at L.A.'s Shubert Theatre.

The show toured from Maine to Florida; from Alaska to California; from Hawaii to New York, and most everywhere in between. For his work in A Chorus Line, Mark recieved critical acclaim accross the country, appearing on E!TV's Behind the Scenes and the Arsenio Hall Show.

After Ninety-nine cities, six hundred performances, and two and a half years, Mark kissed the line goodbye when the tour ended

Mark Santillano's Mike impresses with his acrobatics...
- Jeffrey Mayhook, Anchorage Daily News

Mark Santillano is the most athletic dancer, performing astounding backflips as Mike during "I Can Do That."
- Dan Goddard, San Antonio Express News

Mark Santillano as Mike gives the production a big boost for a start in his solo "I Can Do That."
- The Grand Rapids Press

Santillano flips, flops, and practically knocks himself out for every performance in his rendition of "I Can Do That."
- Mary Evertz, St. Petersberg Times

Early highlights include Mark Santillano's acrobatic spin on "I Can Do That."
- Elias Stimac, Drama-logue

Mark Santillano is lithe in "I Can Do That."
- Jim Farber, Variety

As Mike, Mark Santillano shuffles and back-flips his way through "I Can Do That" as if childhood was just a ball-change away.
- Patti Hartigan, The Boston Globe

Mark Santillano's exuberant "I Can Do That" ... one of the show's half-dozen remarkable solo pieces.
- Gene Grey, Binghamton Press

All the songs are familiar by now, but the performers' enthusiasm made them sparkle, Especially noteworthy were Mark Santillano's "I Can Do That"...
- Carol Cain, Mobile Register

Mark Santillano manages the complete flip in "I Can Do That"...
- Sid Smith, Chicago Tribune

Mark Santillano was properly clarion and bouncy...
- William Albright, The Houston Post

...Mark Santillano's endearing Mike (I Can Do That)...
- Gerald Nachman, The Chronicle, San Francisco

Mark Santillano... practically stopped the show in "I Can Do That"...
- Joe Pollack, St. Louis Post Dispatch